The technical part of the profession of an optician consists in mounting a pair of correcting ophthalmic lenses in an eyeglass frame selected by a wearer.
This mounting comprises at least five main operations:                acquiring the shape of a longitudinal profile representative of the shape of the outline of one of the surrounds of the selected eyeglass frame;        order a lens in accordance with filter needs an/or compensation of vision defect of the wearer;        centering the ophthalmic lens under consideration, i.e. positioning and orienting said longitudinal profile appropriately on the lens, in such a manner that once machined to have this profile and then mounted in its frame, the lens is positioned correctly relative to the corresponding eye of the wearer, so as to enable it to perform as well as possible the optical function for which it is designed;        shaping the lens, i.e. machining its outline to have the shape of the longitudinal profile; and then        assembling the lens together with the frame.        
With rimmed eyeglass frames, the surround (or “rim”) is designed to surround the entire periphery of the lens. Shaping then involves a beveling operation which consists in forming an engagement ridge all along the edge face of the lens for the purpose of engaging in a groove, commonly known as a bezel, that runs around the inside face of the rim of the eyeglass frame.
With half-rimmed eyeglass frames, the surround comprises a half-rim that matches the top portion of the outline of the lens, and a string that runs along the bottom portion of the outline of the lens in order to hold the lens against the half-rim. Shaping then involves a grooving operation that consists in forming an engagement groove along the edge face of the lens, with the top portion of the groove serving to receive a ridge provided along the bottom face of the half-rim and with the bottom portion of the groove serving to receive the string.
Neither of those two methods is really flexible.
Indeed, the shape of the selected frame rigidly dictates the range of lenses which can be selected. For instance, if the frame presents a high curvature, the optician is compelled to choose a lens blank that also presents a high curvature. Because all combinations of lens are not accessible with the right curvature and diameter of the surrounds of the selected frame, some people can not select all the optician's frames, because of their vision deficiencies.
Another problem of the known solutions is that the assembly of the lenses into the frame put constraints on the lenses. That is why it is necessary to select the proper lens geometry and the right material as a function of the characteristics of the frame. For example, all lens edge thicknesses are not compatible with half-rimmed frames.
Moreover, once the eyeglasses are assembled, it is not easy for wearers to modify the aesthetical aspect of their piece of eyewear.
In addition to these various drawbacks, such an assembly has a major disadvantage that we would like to solve.
This disadvantage mainly affects lenses for myopic people, whose thicknesses at the edges are great.
Indeed, it may be observed that the light rays which enter the interior of the ophthalmic lenses and that are reflected on the edges of the lenses generate light halos, for instance in the form of milfoil, called “myopic ring”. These rings, created by total internal reflections in the lenses, exit by the front faces of lenses and are quite visible.
Thus these halos are not only unsightly (for people who look at the wearer), but also unpleasant for the wearer (especially when he sees himself on photos taken with a raking light).